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Biomedical subjects

W Lang

Publications and source records attributed to W Lang.

At least 271 records · Page 15Linked to original sources
PubMed1987

Initial experience with technetium-99m HM-PAO brain SPECT.

Technetium-99m hexamethylpropyleneamineoxime ([99mTc]HM-PAO) brain single photon emission computed tomography (SPECT) was performed with a dual head rotating scintillation camera. Normal tracer distribution and side/side differences of counting rates were obtained in 11 healthy volunteers. Almost stable gray/white matter ratios were found (1.97-2.1) in one normal subject during 2 hr after tracer administration. Eighty-three investigated patients had the following diagnoses (in parentheses is percent of positive findings in each group): cerebral vascular disease 18 (94.4%), epilepsy 23 (82.6%), extrapyramidal disorders 8 (100%), dementia 12 (100%), headache 11 (63.6%), psychiatric disorders 11 (27.3%). In addition, SPECT was performed in 28 male volunteers during motor or visual imagery tasks and a significant increase (p = 0.035) of relative tracer deposition was observed in the left inferior occipital region during visual imagery when compared with motor imagery. The results indicate that [99mTc]HM-PAO SPECT is valuable for demonstrating pathologic and physiologic changes of the brain.

Adult↗
PubMed1986

Distribution of serotonin-1A receptors in the monkey and the postmortem human hippocampal region. A quantitative autoradiographic study using the selective agonist [3H]8-OH-DPAT.

Serotonin-1A receptors were visualized and their anatomical distribution mapped within the monkey and the human hippocampus by using in vitro receptor autoradiography of the selective agonist [3H]8-OH-N,N-dipropyl-2-aminotetralin ([3H]8-OH-DPAT). The results show high densities of serotonin-1A receptors heterogeneously distributed in different subfields and layers of the monkey and the human hippocampal region. High densities are found in the molecular layer of area dentata, all layers of regio superior and the subiculum, parasubiculum, and layers 2, and 4 through 6 of the entorhinal area. In the human hippocampus, a distinct band of [3H]8-OH-DPAT binding sites is present in the subgranular zone of the area dentata. The similar anatomical distribution of [3H]8-OH-DPAT binding sites in the monkey and the human hippocampal region suggests that the serotonin-1A receptor is phylogenetically well preserved and indicates that this receptor may mediate action(s) of serotonin in the primate, including the human hippocampal region.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1986

Distribution of neurons and axons immunoreactive with antisera against neuropeptide Y in the normal human hippocampus.

The detailed distribution of neuropeptide tyrosine (neuropeptide Y; NPY) immunoreactive neurons and fibers is given for the normal human hippocampus. These neuronal elements are detected by a polyclonal antibody raised against the unconjugated peptide and controls were obtained by using liquid phase absorption immunocytochemistry. The description covers the distribution in the area dentata, the hippocampal subfields CA3 and CA1, the subicular complex, and the entorhinal area. Each region is distinct in its NPY content. In general, the hippocampal NPY immunoreactive neurons fall into distinct classes--large hilar neurons; cortical small bipolar or bitufted neurons; medium-sized multipolar neurons in the deep cortical layers; and finally the distinct, small bipolar NPY neurons of the white matter bundles. None of the NPY neurons are pyramidal; many are likely to be local circuit neurons, but some appear to have extrinsic connections. The NPY immunoreactive axonal innervation is dense throughout the hippocampus but shows distinct regional differences in the hippocampal subdivisions. The area dentata has hilar NPY immunoreactive neurons and radial varicose fibers scattered throughout without a clear laminar preference. Subfield CA3 is comparatively the weakest NPY-containing region and contrasts with CA1, which is well endowed with reactive neurons and a rich and unusual axonal innervation, with distinct laminar axonal specializations. The subicular complex is well endowed with cells and fibers and the parasubiculum consistently displays unusually heavy NPY innervation. The entorhinal area exhibits a rich cortical distribution pattern, like that previously described for the human cerebral cortex (Chan-Palay et al; J. Comp. Neurol. 238:382-390, '85a,b). The fimbria, alveus, and angular bundle have NPY neurons embedded within the white matter. Like the NPY immunoreactive innervation of the hippocampal regions of laboratory animals, the human NPY innervation seems to follow a common fundamental pattern with respect to cell locations, cell morphology, and axonal innervation. The difference, however, is the greater complexity and profusion of the NPY-immunoreactive axonal plexuses in the human hippocampus. This rich peptide network within the hippocampus with likely extrahippocampal interconnections raises questions concerning coexistence with other neuroactive substances, the functions of such substantial networks, and how they are altered in human neurological disease.

Aged↗
PubMed1986

Distribution of altered hippocampal neurons and axons immunoreactive with antisera against neuropeptide Y in Alzheimer's-type dementia.

This paper provides detailed information on the distribution of neuropeptide tyrosine (neuropeptide Y; NPY) immunoreactive neurons and fibers in the hippocampal region of eight neuropathologically confirmed cases of Alzheimer's-type dementia (ATD) at postmortem. These neuronal networks are detected by a polyclonal antibody raised against the unconjugated peptide and controls were obtained by using liquid phase absorption immunocytochemistry. The description covers the subfields area dentata, CA3 and CA1, the subicular complex, and the entorhinal area. The hippocampal regions in which the NPY-i neuron networks are most severely affected are the hilus, CA1, the parasubiculum, and the entorhinal cortex. Less obvious reductions occurred in CA3, subiculum, and the presubiculum. Parallel semiquantitative estimates were made of the numbers of neuritic plaques and neurofibrillary tangles in the other hippocampus of the brains in every ATD case. The areas of heaviest pathological changes by these indices are CA1 and the entorhinal cortex. The subicular complex CA3 and the area dentata are less affected. These findings show that the areas with the most severe loss of NPY-i neurons and axons, CA1 and the entorhinal cortex, are the same as those areas most severely affected by the other indices of ATD. Thus NPY-i networks are involved in the ATD disease process. However, other NPY-i networks survive, in some subfields better than in others. The cumulative evidence suggests a population of hippocampal peptide neurons that are remarkably resistant in terminal neurological disease. These neurons have the capability to participate in the maintenance of minimal functioning circuits in target areas of the disease and as such hold significant links for our understanding of synaptic plasticity in disease.

Aged↗
PubMed1986

[Experience with percutaneous needle muscle biopsy in pediatrics: alternatives to open biopsy?].

Over 14 months the authors have performed 22 needle muscle biopsies using the Bergström needle. Sufficient material was obtained for histological, histochemical and electron microscopic examination. The biopsies can be done as an outpatient procedure under local anesthetic, and with sedation in infants and young children. The technique is safe, quick and well tolerated and leaves only a very small scar. It provides adequate information for almost all diagnostic purposes in neuromuscular disease. The few indications for open muscle biopsy are discussed.

Adolescent↗
PubMed1986

Bereitschaftspotential preceding speech after holding breath.

Cerebral potentials prior to speaking were recorded in 36 healthy righthanded subjects. Subjects began holding breath at irregular intervals prior to the voluntary onset of speech. This was done in order to avoid respiration-related potential shifts. The Bereitschaftspotential (BP) or readiness potential started already 2 s prior to the onset of speaking and was present over either hemisphere. During the last 100 to 200 ms of preparation period, the BP became significantly lateralized towards the left hemisphere. The close temporal relation to speech onset characterized this hemispheric lateralization to be an indicator of the final motor mechanisms for speech. Still, the BP was a bilateral phenomenon, i.e. it was also present over the right hemisphere, indicating involvement of the non-dominant hemisphere as well. The data are compatible with the view of an early bihemispheric motor preparation for speech followed by a late left hemisphere preponderance as the final common pathway.

Adult↗
PubMed1986

Distinction of two CD3-monoclonal antibodies in respect to the effectivity to modulate the induction of IgM- and gamma-interferon synthesis.

Monoclonal antibodies which specifically bind to epitopes within the T3-antigen complex (CD3 mAb) are excellent tools to analyse mechanisms of T-cell activation and of the interactions between T-cells, B-cells, accessory cells and intermediating immunefactors. In the present study we could show, that the CD-3 mAbs BMA 030 and BMA 031 are highly effective in modulating immunereactions, similar to antibodies directed to the T4-antigen (CD4-mAb) or the T8-antigen (CD8-mAbs) respectively. The data substantiate that depending on the experimental system BMA 030 and BMA 031 are clearly distinctive in their efficacy to modulate immunereactions. For therapeutical use of CD-3-monoclonal antibodies in organ transplantation those clone-specific differences of mAbs with identical binding specificity might cause for crucial differences in clinical applicability.

Antibodies, Monoclonal↗
PubMed1986

[Biopsy findings in kidney transplants after treatment with cyclosporin A].

51 renal transplant biopsies of 37 patients immunosuppressed with Cyclosporin A were histologically reevaluated. Lesions related as well as unrelated to Cyclosporin A treatment were found. Cyclosporin A related findings corresponding to the so-called Cyclosporin A nephropathy were divided into early postoperative (diffuse fibrosis), acute (toxic tubulopathy and others) and chronic changes (arteriolopathy, striped fibrosis with tubular atrophy). Since there is often a combination of Cyclosporin A related and unrelated lesions, it is necessary to define the main lesion in the individual case. Accordingly, the following diagnostic groups were present in the biopsies: Cyclosporin A nephropathy (19 cases), rejection nephropathy (18), rejection and Cyclosporin A nephropathy (9), acute renal failure (3) and other diagnoses (2 cases). For the further management of the patients, the exact diagnosis of Cyclosporin A related and unrelated pathology is important in renal biopsies.

Acute Kidney Injury↗
PubMed1986

Risk factors in follicular thyroid carcinomas. A retrospective follow-up study covering a 14-year period with emphasis on morphological findings.

One hundred sixty-seven patients with follicular carcinomas and 88 with atypical adenomas of the thyroid have been followed up for up to 14 years. The influence of tumor invasiveness; tumor extent at time of presentation, including degree of metastatic spread; and age of patients have been evaluated by determining the rate at which distant metastases or deaths occurred during the later course of disease after surgery had been performed. The degree of tumor invasiveness has been found to be of great prognostic weight. Atypical adenomas did not show recurrences during the time of observation. The most important diagnostic distinction made with regard to prognosis was found to be between minimally invasive (encapsulated) and extensively invasive carcinomas.

Adolescent↗
PubMed1986

Electrophysiological evidence for right frontal lobe dominance in spatial visuomotor learning.

Slow negative potential shifts were recorded together with the error made in motor performance when two different groups of 14 students tracked visual stimuli with their right hand. Various visuomotor tasks were compared. A tracking task (T) in which subjects had to track the stimulus directly, showed no decrease of error in motor performance during the experiment. In a distorted tracking task (DT) a continuous horizontal distortion of the visual feedback had to be compensated. The additional demands of this task required visuomotor learning. Another learning condition was a mirrored-tracking task (horizontally inverted tracking, hIT), i.e. an elementary function, such as the concept of changing left and right was interposed between perception and action. In addition, subjects performed a no-tracking control task (NT) in which they started the visual stimulus without tracking it. A slow negative potential shift was associated with the visuomotor performance (TP: tracking potential). In the learning tasks (DT and hIT) this negativity was significantly enhanced over the anterior midline and in hIT frontally and precentrally over both hemispheres. Comparing hIT and T for every subject, the enhancement of the tracking potential in hIT was correlated with the success in motor learning in frontomedial and bilaterally in frontolateral recordings (r = 0.81-0.88). However, comparing DT and T, such a correlation was only found in frontomedial and right frontolateral electrodes (r = 0.5-0.61), but not at the left frontolateral electrode. These experiments are consistent with previous findings and give further neurophysiological evidence for frontal lobe activity in visuomotor learning. The hemispherical asymmetry is discussed in respect to hemispherical specialization (right frontal lobe dominance in spatial visuomotor learning).

Contingent Negative Variation↗